The invention relates to valves having moving parts that are subject to loads. Typical fluidic valves have parts that are configured to avoid leakage of fluids. As a valve is cycled between valve states, however, the loads placed on the moving parts cause wear. Loads can be substantial on moving parts, typically a stator and a rotor, of a valve used in analytical instruments. Portions of some analytical instruments operate at high pressure, often requiring application of high pressure at valve-part interfaces. For example, a high performance liquid chromatography (HPLC) pump typically operates at up to 1,000 to 5,000 pounds per square inch (psi); higher pressure chromatography apparatus operate at pressures up to 10,000 psi or greater.
As the pressure of a system increases, the wear on the moving parts of a valve tends to increase and the valve's expected cycle lifetime is reduced. Many valves operating at very high pressures can only withstand 150,000 cycles.